Windstream
Ojk's Precalculus Study Page: Sum and Difference Formulas for Tangent
This tutorial introduces the sum and differnce formulas for tangent, and gives several examples of problems to be solved as well as proving other identities. Assumes knowledge of the sum and difference formulas for sine and cosine.
Math Medics
S.o.s. Math: Trigonometry: The Addition Formulas
This math lesson contains a list of trigonometric addition formulas. Includes example problems involving these formulas along with solutions.
Wolfram Research
Wolfram Math World: Trigonometric Addition Formulas
This tutorial offers formulas and explanations on trigonometric addition formulas and features an easy way to remember the sine and cosine addition formulas using matrices.
Windstream
Ojk's Precalculus Study Page: Sum and Difference Formulas for Sine and Cosine
An introduction to trigonometric identities, beginning with the sum and difference formulas. Some of the formulas are proven, some are left to the reader. Includes several examples and pictures.
Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Sum and Difference Formulas
Twenty problems are presented for practice working with sum and difference formulas for sine, cosine, and tangent.
Khan Academy
Khan Academy: Find Trig Values Using Angle Addition Identities
Find the trigonometric values of various angles that (while they are not special angles) can be expressed as the sum or difference of special angles. Students receive immediate feedback and have the opportunity to try questions...
Khan Academy
Khan Academy: Using the Trig Angle Addition Identities
Find the trig values of sums of angles whose individual trig values are known. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Illustrative Mathematics
Illustrative Mathematics: G Gpe, N Rn, F Tf Coordinates of Equilateral Triangles
In this task, students are asked if there is an equilateral triangle ABC where two vertices are on the x-axis, and all vertices have integer coordinates. Aligns with G-GPE.B, N-RN.B, and F-TF.C.9.
Illustrative Mathematics
Illustrative Mathematics: F Tf Sum and Difference Angle Formulas
The goal of this task is to have students derive the addition and subtraction formulas for cosine and tangent, and the subtraction formula for cosine, from the sum formula for sine. Aligns with F-TF.C.9.
CK-12 Foundation
Ck 12: Trigonometry: Tangent Sum and Difference Formulas
[Free Registration/Login may be required to access all resource tools.] Here you'll learn to rewrite tangent functions with addition or subtraction in their arguments in a more easily solvable form.
CK-12 Foundation
Ck 12: Trigonometry: Sine Sum and Difference Formulas
[Free Registration/Login may be required to access all resource tools.] Sine of a sum or difference related to a set of cosine and sine functions. Here you'll learn to rewrite sine functions with addition or subtraction in their...
CK-12 Foundation
Ck 12: Trigonometry: Cosine Sum and Difference Formulas
[Free Registration/Login may be required to access all resource tools.] Examples, videos, and practice problems covering cosine of a sum or difference related to a set of cosine and sine functions. Here you'll learn to rewrite cosine...
CK-12 Foundation
Ck 12: Trigonometry: Applications of Sum and Difference Formulas
[Free Registration/Login may be required to access all resource tools.] Solving equations and verifying identities with the sum and difference formulas.